Kronosaurus queenslandicus (Longman 1924) Turonian, early Late Cretaceous, ~10 m in length was originally considered ~13 m in length. In any case, Kronosaurus was among the largest of the pliosaurs. Derived from a sister to Pliosaurus (see below), Brachauchenius and Trinacromerum, Kronosaurus represents the last of its lineage.
Distinct from Brachauchenius, the skull of Kronosaurus was relatively larger with teeth the size of bananas. The postorbital region was both taller and longer to provide space for larger muscles to work the larger jaws. The typically vertical postorbital/squamosal process of the jugal was depressed horizontally in line with the maxilla. The squamosal also dropped so the lateral temporal fenestra was essentially eliminated. The coronoid process of the mandible was located further anteriorly below the anterior rim of the temporal region.
The cervicals and the entire vertebral column were more robust. The torso was elongated with more dorsal vertebrae and ribs. The gastralia were reduced between the enlarged ventral plates (coracoid and pubis).
The scapula was smaller. The coracoid was larger. The forelimb paddle was relatively shorter and more symmetrical.
The ilium had an expanded dorsal rim. The pubis was greatly enlarged, more so than the ischium. The femur was only slightly longer than the humerus.
Kronosaurus was no doubt very large, but the specimen was far from complete. The mounted skeleton at Yale has been nicknamed, "Plastersaurus," due to the large amounts of plaster used to create the illusion of a complete skeleton. Thus, some of the above description may depend on the sculptor's vision and bias.
The family tree of the Enaliosauria is here. The complete reptile family tree is here.